Salsa and pico de gallo are staples at my house and most local restaurants: many furriners aren't sure what is the difference. Pico, pictured top, is generally made up of fresh raw tomatoes, onions, jalapenos and cilantro chopped up into tiny chunks and served cold or room temp, sometimes marinated in lime juice. Spoon it onto a chip or stuff it into your burrito, it is not "Mexican coleslaw" (as we used to tell unsuspecting tourists). It is a raw veggie garnish you eat like dip. Oddly, pico is nearly the same (ingredients, flavor, mixture ratio) where ever you eat it in the southwest. You can also mix it with avocados and make great guacamole, spoon it into tacos, burritos, eggs, etc. To natives, it does not taste particularly spicy....hubster, who likes hot foods, adds a ton of jalapenos to his.
Salsa, pictured below, contains similar ingredients to pico de gallo, (often with the addition of garlic or other flavors- see below for comments) yet is always in a more liquid, less solid state. Some versions are strained and have no solid particulates at all; some versions are slightly chunkier, but always more liquid than solid. It is like gazpacho but spicier and is never eaten as soup. It can be served cooked (often made of fire roasted ingredients) or raw. Each restaurant's salsa has a different flavor, a different style, and considerable time is spent arguing or comparing whose is best and why. Salsa not only varies from one restaurant to another, but from one culinary region to another. In New Mexico, it often comes in red or green (depending or whether made with red chile or green chile) or hatch- another kind of chile. ("You say c-h-i-l-e, I say c-h-i-l-i......tomato, to-mah-to"). In California, it often has beans or corn in it. You can dip chips in salsa, spoon it into any Mexican dish, like pico - only salsa will be a liquid flavor, while pico will be a solid vegetable component (like the lettuce and tomatoes on a taco.) In Italian food, you use the same basic ingredients: tomatoes, basil, garlic, olive oil, all combined in different ways to make spaghetti sauce or a garden salad or bruschetta. It's the same with salsa and pico. To compare to a hamburger: pico is like the pickles and lettuce, while salsa is like the ketchup and mustard. You can make your own- numerous recipes float the web - or buy one that's in a jar. Arriba is my hands-down favorite, all-purpose, eat it every day, go-to brand. It's available in grocery stores around here, comes in many different hotness levels and flavors/styles. I like regular medium. Brother-in-law enrolled us in the "salsa of the month " club, and while a cute idea, most of the ones featured were too sweet, too weird- artichoke or peach additions- and just collect dust in the pantry. I know Pace Picante Sauce claims to be the national salsa of Texas, but I just don't like it and never have. It has a weird bitter after taste and the veggies in it are green and slimy and look like boogers.
What is picante sauce? Another word for salsa.
What is "hot sauce" ? Sometimes it is a salsa, sometimes it is a thin strained (never chunky or with particulates) smooth liquid that is very spicy, comes in many different flavors/styles/ingredients, and is often added to other dishes (for ex, to tacos). Often it has a vinegar base. Salsa is more likely to be fresh or used as a dip, whereas hot sauce is always preserved and comes in a bottle or package. There are southwestern hot sauces, but there are hot sauces in Cajun cooking, many Asian ethnic cuisines, Jamaican cooking, etc.
Santa Fe School of Cooking - I've been here several times, taken classes ( tons of fun!) and love to buy their stuff